Disk device

ABSTRACT

A disk device according to one embodiment includes a magnetic disk, a magnetic head, and a flexible printed circuit board. The flexible printed circuit board is electrically connected to the magnetic head. The flexible printed circuit board includes a first layer, a second layer having conductive property, and a third layer having insulation property. The first layer includes a first surface having insulation property. The second layer overlays the first surface, and includes a first conductor and a second conductor spaced from the first conductor. The third layer covers at least a part of the first surface and at least a part of the second layer. The flexible printed circuit board is provided with a first hole that is located between the first conductor and the second conductor with spacing from the second layer and penetrates the third layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2021-137351, filed on Aug. 25, 2021; theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a disk device.

BACKGROUND

In disk devices such as a hard disk drive, information is read andwritten from and to a magnetic disk with a magnetic head. Such a diskdevice includes, for example, a flexible printed circuit board thatelectrically connects a controller and the magnetic head. The flexibleprinted circuit board is provided with a plurality of conductors such aswiring and pads.

For example, along with improvement in the function of the disk device,the conductors may be mounted at a higher density on the flexibleprinted circuit board. In such a case, a shortened distance between twoadjacent conductors may affect the performance of the flexible printedcircuit board.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary perspective view illustrating an HDD according toa first embodiment;

FIG. 2 is an exemplary plan view schematically illustrating an FPC ofthe first embodiment;

FIG. 3 is an exemplary plan view schematically illustrating a part of afirst connection part of the first embodiment;

FIG. 4 is an exemplary cross-sectional view illustrating a part of thefirst connection part of the first embodiment taken along the line F4-F4of FIG. 3 ;

FIG. 5 is an exemplary cross-sectional view illustrating a part of thefirst connection part of the first embodiment taken along the line F5-F5of FIG. 3 ;

FIG. 6 is an exemplary cross-sectional view illustrating a part of thefirst connection part of the first embodiment taken along the line F6-F6of FIG. 3 ;

FIG. 7 is an exemplary cross-sectional view illustrating a part of afirst, connection part according to a second embodiment; and

FIG. 8 is an exemplary cross-sectional view illustrating a part of afirst connection part according to a third embodiment.

DETAILED DESCRIPTION

According to one embodiment, a disk device includes a magnetic disk, amagnetic head, and a flexible printed circuit board. The magnetic headis configured to read and write information from and to the magneticdisk. The flexible printed circuit board is electrically connected tothe magnetic head. The flexible printed circuit board includes a firstlayer, a second layer having conductive property, and a third layerhaving insulation property. The first layer includes a first surfacehaving insulation property. The second layer overlays the first surfaceand includes a first conductor and a second conductor spaced from thefirst conductor. The third layer covers at least a part of the firstsurface and at least a part of the second layer. The flexible printedcircuit board is provided with a first hole that is located between thefirst conductor and the second conductor with spacing from the secondlayer and penetrates the third layer.

First Embodiment

Hereinafter, the first embodiment is described with reference to FIGS. 1to 6 . Note that, in the present specification, constituent elementsaccording to the embodiments and descriptions of the constituentelements may be described in a plurality of expressions. The constituentelements and description thereof are examples, and are not limited bythe expressions of the present specification. The constituent elementsmay also be identified with names different from those in the presentspecification. In addition, the constituent elements may be described byusing an expression different from the expression of the presentspecification.

FIG. 1 is an exemplary perspective view illustrating a hard disk drive(HDD) 10 according to the first embodiment. The HDD 10 is an example ofthe disk device, and may also be referred to as an electronic device, astorage device, an external storage device, or a magnetic disk device.The disk device is not limited to the HDD 10.

The RDD 10 includes a casing 11, a plurality of magnetic disks 12, aspindle motor 13, a plurality of magnetic heads 14, an actuator assembly15, a voice coil motor (VCM) 16, a ramp load mechanism 17, a flexibleprinted circuit board (FPC) 18, and a printed wiring board (PCB) 19.

The casing 11 includes a base 21, an inner cover 22, and an outer cover23. The base 21 is a bottomed container made of a metal material such asan aluminum alloy, and has a bottom wall 25 and a side wall 26. Thebottom wall 25 is formed in a substantially rectangular (quadrangular)plate-like shape. The side wall 26 protrudes from an edge of the bottomwall 25. The bottom wall 25 and the side wall 26 are integrally formed.

The inner cover 22 and the outer cover 23 are made of a metal materialsuch as an aluminum alloy, for example. The inner cover 22 is attachedto an end of the side wall 26 with, for example, a screw. The outercover 23 covers the inner cover 22 and is airtightly fixed to the end ofthe side wall 26 by welding, for example.

The casing 11 is sealed inside. Inside the casing 11, the magnetic disk12, the spindle motor 13, the magnetic head 14, the actuator assembly15, the VCM 16, the ramp load mechanism 17, and the FPC 18 are placed.

The inner cover 22 has a vent 22 a. Further, the outer cover 23 has avent 23 a. After components are mounted inside the base 21 and the innercover 22 and the outer cover 23 are attached to the base 21, air insidethe casing 11 is removed through the vents 22 a and 23 a. Further, thecasing 11 is filled with a gas different, from air.

The gas filled inside the casing 11 is, for example, a low density gashaving a density lower than that of air, an inert gas having lowreactivity, or the like. For example, the casing 11 is filled withhelium. The casing 11 may be filled with another fluid. The inside ofthe casing 11 may be maintained at vacuum, low pressure close to vacuum,or negative pressure lower than atmospheric pressure.

The vent 23 a of the outer cover 23 is closed by a seal 28. The seal 28hermetically seals the vent 23 a to prevent the leakage of the fluidfilled in the casing 11 from the vent 23 a.

The magnetic disk 12 is, for example, a disk having magnetic recordinglayers provided on an upper surface and a lower surface thereof. Thediameter of the magnetic disk 12 is, for example, 3.5 inches; however,the diameter is not limited to the example. The plurality of magneticdisks 12 is stacked at intervals.

The spindle motor 13 supports and rotates the magnetic disks 12 thusstacked. The magnetic disks 12 are held in a hub of the spindle motor 13by, for example, a clamp spring.

The magnetic head 14 records and reproduces information on and from therecording layer of the magnetic disk 12. Stated differently, themagnetic head 14 reads and writes information from and to the magneticdisk 12. The magnetic head 14 is mounted on the actuator assembly 15.

The actuator assembly 15 is rotatably supported by a support shaft 31disposed at a position spaced from the magnetic disk 12. The VCM 16rotates the actuator assembly 15 to place the same at a desiredposition. When the magnetic, head 14 moves to the outermost periphery ofthe magnetic disk 12, the ramp load mechanism 17 holds the magnetic head14 at an unload position spaced from the magnetic disk 12.

The actuator assembly 15 includes an actuator block 35, a plurality ofarms 36, and a plurality of head suspension assemblies 37. The headsuspension assembly 37 is hereinafter referred to as a suspension 37.The suspension 37 may also be referred to as a head gimbal assembly(HGA).

The actuator block 35 is rotatably supported by the support shaft 31through a bearing, for example. The plurality of arms 36 protrudes fromthe actuator block 35 in a direction substantially orthogonal to thesupport shaft 31. Another configuration is possible in which theactuator assembly 15 is divided and the arm 36 protrudes from each ofthe plurality of actuator blocks 35.

The plurality of arms 36 is placed at intervals in a direction in whichthe support shaft 31 extends. Each of the arms 36 is formed in aplate-like shape which allows the arm to enter an interval between theadjacent magnetic disks 12. The arms 36 extend substantially inparallel.

The actuator block 35 and the arms 36 are integrally made of, forexample, aluminum. Note that the material of the actuator block 35 andthe arms 36 is not limited to the example.

A voice coil of the VCM 16 is provided on a protrusion protruding fromthe actuator block 35 to the other side of the arm 36. The VCM 16includes a pair of yokes, the voice coil disposed between the yokes, anda magnet provided on the yoke.

The VCM 16 rotates the actuator assembly 15 as described above. In otherwords, the VCM 16 rotates (moves) the actuator block 35, the arm 36, andthe suspension 37 together.

The suspension 37 is attached to an end of the corresponding arm 36 andprotrudes from the arm 36. Thereby, the plurality of suspensions 37 isplaced at intervals in the direction in which the support shaft 31extends.

Each of the suspensions 37 includes a base plate 41, a load beam 42, anda flexure 43. Further, the magnetic head 14 is mounted on a tip of thesuspension 37.

The base plate 41 and the load beam 42 are made of, for example,stainless steel. Note that the materials of the base plate 41 and theload beam 42 are not limited to the example. The base plate 41 is formedin a plate-like shape and is attached to the end of the arm 36. The loadbeam 42 is formed in a plate-like shape thinner than the base plate 41.The load beam 42 is attached to an end of the base plate 41 andprotrudes from the base plate 41.

The flexure 43 is formed in an elongated belt shape. Note that the shapeof the flexure 43 is not limited to the example. The flexure 43 is astacked plate including a metal plate (backing layer) made of stainlesssteel or the like, an insulating layer formed on the metal plate, aconductive layer formed on the insulating layer and constituting aplurality of wirings (wiring patterns), and a protective layer(insulating layer) covering the conductive layer.

A gimbal part (elastic support part) that is positioned on the load beam42 and is displaceable is provided in one end of the flexure 43. Thegimbal part is provided in the tip of the suspension 37 and the magnetichead 14 is mounted on the gimbal part. The other end of the flexure 43is connected to the FPC 18. This allows the FPC 18 to be electricallyconnected to the magnetic head 14 through the wiring of the flexure 43.

The PCB 19 is, for example, a rigid board such as a glass epoxy board,and is a multilayer board, a build-up board, or the like. The PCB 19 isprovided external to the casing 11 and is attached to the bottom wall 25of the base 21. The PCB 19 is attached to the bottom wall 25 with, forexample, a plurality of screws.

For example, an interface (I/F) connector 51, a controller 52, and arelay connector 53 are mounted on the PCB 19. Other components may bemounted on the PCB 19.

The I/F connector 51 is a connector conforming to an interface standardsuch as serial ATA (SATA), and is connected to an I/F connector of ahost computer. The HOD 10 receives power supply from the host computerthrough the I/F connector 51, and sends and receives various pieces ofdata to and from the host computer.

The controller 52 is, for example, a system-on-chip (SoC), and includesa read/write channel (RWC), a hard disk controller (HDC), and aprocessor. Note that the RWC, the HDC, and the processor may be separatecomponents.

The processor of the controller 52 is, for example, a central processingunit (CPU). The processor performs overall control of the HDD 10according to firmware stored in advance in the ROM, for example. Forexample, the processor loads the firmware of the ROM into the RAM, andcontrols the magnetic head 14, the RWC, the HDC, and other partsaccording to the firmware thus loaded.

The relay connector 53 is electrically connected to various componentsplaced inside the casing 11, for example, through a connector providedon the bottom wall 25. This allows the PCB 19 to be electricallyconnected to the spindle motor 13, the magnetic head 14, the actuatorassembly 15, the VCM 16, and the FPC 18 placed inside the casing 11.

FIG. 2 is an exemplary plan view schematically illustrating the FPC 18of the first embodiment. As illustrated in FIG. 2 , the FPC 18 is formedin a substantially L-shaped belt shape in a natural state where the FPC18 is detached from the other components and no external force acts.Note that the shape of the FPC 18 is not limited to the example. The FPC18 includes a first connection part 61, a second connection part 62, andan intermediate part 63.

The first connection part 61 is provided, for example, in one end of theFPC 18 in a direction in which the FPC 18 extends. The first connectionpart 61 is attached to the actuator block 35 with, for example, a screw.The first connection part 61 is electrically connected to the VCM 16 andthe flexure 43.

The first connection part 61 has a plurality of insertion holes 64. Theinsertion holes 64 penetrate the first connection part 61. For example,the screw inserts through the insertion hole 64 to attach the firstconnection part 61 to the actuator block 35. Note that the insertionhole 64 is not limited to the example. For example, a pin attached tothe actuator block 35 through the insertion hole 64 may be fixed to thefirst connection part 61 by soldering.

The second connection part 62 is provided, for example, in the other endof the FPC 18 in the direction in which the FPC 18 extends. The secondconnection part 62 is attached to the bottom wall 25 with, for example,a screw. The second connection part 62 is electrically connected to thePCB 19 through, for example, a connector provided on the bottom wall 25.

The intermediate part 63 is provided between the first connection part61 and the second connection part 62. The intermediate part 63 extendsin a belt shape and bends between the first connection part 61 and thesecond connection part 62 in accordance with rotation of the actuatorblock 35.

As illustrated in the drawings, in the present specification, an X-axis,a Y-axis, and a Z-axis are defined for convenience. The X-axis, theY-axis, and the Z-axis are orthogonal to one another. The X-axis isalong the width of the intermediate part 63 in the natural state. TheY-axis is along the length of the intermediate part 63 in the naturalstate. The Z-axis is along the thickness of the FPC 18 in the naturalstate.

Further, in the present specification, an X-direction, a Y-direction,and a Z-direction are defined. The X-direction is a direction along theX-axis and includes a +X-direction indicated by an arrow of the X-axisand a −X-direction which is an opposite direction of the arrow of theX-axis. The Y-direction is a direction along the Y-axis and includes a+Y-direction indicated by an arrow of the Y-axis and a −Y-directionwhich is an opposite direction of the arrow of the Y-axis. TheZ-direction is a direction along the Z-axis and includes a +Z-directionindicated by an arrow of the Z-axis and a −Z-direction which is anopposite direction of the arrow of the Z-axis.

The first connection part 61 is connected to an end of the intermediatepart 63 in the +Y-direction and extends in the +Y-direction from theend. The second connection part 62 is connected to an end of theintermediate part 63 in the −Y-direction and extends in the +X-directionfrom the end. Note that the first connection part 61 and the secondconnection part 62 are not limited to the example.

The HDD 10 further includes a plurality of preamplifiers 65, a relayconnector 66, a sensor 67, and a plurality of reinforcing plates 68. Thepreamplifier 65 is an example of a component and may also be referred toas a head amplifier. The reinforcing plate 68 is an example of a wall.

The preamplifier 65 is mounted on the first connection part 61. Thepreamplifier 65 is electrically connected to the flexure 43, forexample, through a wiring and pads of the FPC 18. In addition, thepreamplifier 65 is electrically connected to the magnetic head 14through the flexure 43. The preamplifier 65 amplifies a write signal tosend the write signal to the magnetic head 14, and amplifies a readsignal sent from the magnetic head 14.

The preamplifier 65 is fixed to the FPC 18 with an underfill 69. Theunderfill 69 is provided and extends between the preamplifier 65 and theFPC 18. A part of the underfill 69 is attached to an edge of thepreamplifier 65 and is located outside the space between thepreamplifier 65 and the FPC 18.

The relay connector 66 and the sensor 67 are mounted on the secondconnection part 62. The relay connector 66 is electrically connected tothe relay connector 53 of the PCB 19, for example, through a connectorprovided on the bottom wall 25. The second connection part 62 is therebyconnected to the PCB 19. The relay connector 66 may be directlyconnected to the relay connector 53 of the PCB 19. The sensor 67detects, for example, temperature and humidity inside the casing 11, andacceleration and angular acceleration of the HOD 10.

The reinforcing plate 68 is made of, for example, a metal such asaluminum or a synthetic resin, and is formed in a plate-like shape. Notethat the reinforcing plate 68 is not limited to the example. Thereinforcing plates 68 are attached to the first connection part 61 andthe second connection part 62. The reinforcing plates 68 improverigidity of the first connection part 61 and the second connection part62.

FIG. 3 is an exemplary plan view schematically illustrating a part ofthe first connection part 61 of the first embodiment. FIG. 4 is anexemplary cross-sectional view illustrating a part of the firstconnection part 61 of the first embodiment taken along the line F4-F4 ofFIG. 3 . FIG. 5 is an exemplary cross-sectional view illustrating a partof the first connection part 61 of the first embodiment taken along theline F5-F5 of FIG. 3 . FIG. 6 is an exemplary cross-sectional viewillustrating a part of the first connection part 61 of the firstembodiment taken along the line F6-F6 of FIG. 3 .

As illustrated in FIG. 4 , the FPC 18 includes a base layer 71, aconductive layer 72, a cover layer 73, ground layer 74, and a coverlayer 75. The base layer 71 is an example of a first layer. Theconductive layer 72 is an example of a second layer. The cover layer 73is an example of a third layer.

The base layer 71 is made of, for example, an insulating material suchas polyimide, and has insulation property. In a case where the FPC 18 isa multilayer FPC, the base layer 71 may have a plurality of insulatinglayers and a plurality of conductive layers.

The base layer 71 has an upper surface 71 a and a lower surface 71 b.Note that “upper” and “lower” in the present specification areconvenient expressions on the basis of the vertical direction in FIG. 4, and are not intended to limit the direction, Position, and otherconditions. The upper surface 71 a is an example of a first surface.

The upper surface 71 a is a surface of the base layer 71 facing theZ-direction. The lower surface 71 b is located on the opposite side ofthe upper surface 71 a and is a surface of the base layer 71 facing the−Z-direction. Since the base layer 71 is made of an insulating material,the upper surface 71 a has insulation property. For example, in a casewhere the FPC 18 is a multilayer FPC, a conductor may be exposed on theupper surface 71 a.

On the lower surface 71 b, the ground layer 74 made of a conductor suchas copper is provided. The cover layer 75 is made of, for example, aninsulating material such as polyimide to cover the ground layer 74. In acase where the FPC 18 is a multilayer FPC, the ground layer 74 may beprovided inside the base layer 71.

The conductive layer 72 is made of, for example, a conductor such ascopper and has conductive property. The conductive layer 72 overlays theupper surface 71 a of the base layer 71. An adhesive layer may beprovided between the conductive layer 72 and the upper surface 71 a.

The conductive layer 72 includes a plurality of pads 81, 82, 83, and 84,a signal wiring 85, a power supply wiring 86, two gimbal micro actuators(GMA) wirings 87 and 88 illustrated in FIG. 3 , and a conductor 89illustrated in FIG. 6 . Further, the conductive layer 72 includes aplurality of ground wirings 91, 92, and 93 illustrated in FIG. 3 .

The pads 81 and 82 and the GMA wiring 87 are an example of a firstconductor. The pads 83 and 84, the power supply wiring 86, and the GMAwiring 88 are an example of a second conductor. The GMA wiring 87 is anexample of a first wiring. The GMA wiring 88 is an example of a secondwiring. The pads 81, 82, 83, and 84 may also be referred to as lands,terminals, or electrodes.

Each of the pads 81 and 82 is one of pads to which the preamplifier 65is connected. As illustrated in FIG. 4 , a terminal 65 a of thepreamplifier 65 is connected to the pad 81. As illustrated in FIG. 6 , aterminal 65 b of the preamplifier 65 is connected to the pad 82. Theterminals 65 a and 65 b are, for example, solder balls. Note that theterminals 65 a and 65 b are not limited to the example.

The pad 83 illustrated in FIG. 4 is connected to a terminal of the voicecoil of the VCM 16. The pad 83 is connected to the VCM 16 through solder95. That is, the solder 95 is attached to the pad 83. The pad 83 isspaced from the pads 81 and 82.

As illustrated in FIG. 3 , the pad 84 is provided in a substantiallyannular shape along an edge of the insertion hole 64. The pad 84 iscovered with the solder 96 and protected by the solder 96. Note that thepad 84 is not limited to the example. The pad 84 is spaced from the pads81 and 82.

The signal wiring 85 extends along the upper surface 71 a between therelay connector 66 and the preamplifier 65, for example. The signalwiring 85 is connected to the pad 81 or another pad to which thepreamplifier 65 is connected, and sends a read signal and a writesignal. Note that the signal wiring 85 is not limited to the example.The signal wiring 85 is spaced from the pads 83 and 84.

The power supply wiring 86 extends along the upper surface 71 a betweenthe relay connector 66 and the pad 83, for example. The power supplywiring 86 is connected to the pad 83 and supplies power to the VCM 16.Note that the power supply wiring 86 is not limited to the example. Thepower supply wiring 86 is spaced from the pads 81, 82, and 84 and thesignal wiring 85.

The GMA wirings 87 and 88 extend along the upper surface 71 a betweenthe relay connector 66 and the flexure 43, for example. The GMA wirings87 and 88 extend substantially in parallel. The GMA wiring 88 thusextends along the GMA wiring 87. Note that the distance between the twoGMA wirings 87 and 38 may not be constant. The GMA wiring 87 is closerto the preamplifier 65 than the GMA wiring 88.

The GMA wirings 87 and 88 are electrically connected to, for example,the magnetic head 14 of a microwave assisted magnetic recording (MAMR)system or a heat assisted magnetic recording (HANK) system, and the GMAwirings 87 and 88 send a control signal for a laser beam or microwavesource. Note that the GMA wirings 87 and 88 are not limited to theexample.

The conductor 89 illustrated in FIG. 6 is located between the pad 82 andthe GMA wiring 87. The conductor 89 is, for example, an inspectionpattern used for inspection of the FPC 18. Note that the conductor 89 isnot limited to the example, and may be, for example, a wiring.

The ground wirings 91, 92, and 93 are electrically connected to theground. For example, the ground wirings 91, 92, and 93 are electricallyconnected to the ground layer 74 through a via.

As illustrated in FIG. 3 , the ground wiring 91 extends through a regionbetween the pad 81 and the pad 33, a region between the pad 81 and thepad 84, and a region between the pad 81 and the power supply wiring 86.The ground wiring 91 is thus located between the pad 81 and the pad 83and between the pad 81 and the pad 84. The ground wiring 91 is alsolocated between the underfill 69 and the pad 83 and between theunderfill 69 and the pad 84.

The ground wiring 92 is located between the GMA wiring 87 and the GMAwiring 88. The ground wiring 93 is located between the pad 82 and theGMA wiring 87. The ground wirings 92 and 93 extend substantiallyparallel to the GMA wirings 87 and 88. Note that the ground wirings 92and 93 may be shorter than the GMA wirings 87 and 88.

As illustrated in FIG. 4 , the cover layer 73 covers at least a part ofthe upper surface 71 a of the base layer 71 and at least apart of theconductive layer 72. For example, the cover layer 73 covers the signalwiring 85, the power supply wiring 86, the GMA wirings 87 and 83, andthe ground wirings 91, 92, and 93. The cover layer 73 has a lowersurface 73 a and an upper surface 73 b. The lower surface 73 a is anexample of a second surface. The upper surface 73 b is an example of athird surface.

The lower surface 73 a is a surface of the cover layer 73 facing the−Z-direction. The lower surface 73 a faces the upper surface 71 a of thebase layer 71. The upper surface 73 b is located on the opposite side ofthe lower surface 73 a and is a surface of the cover layer 73 facing theZ-direction. The upper surface 73 b forms a surface of the FPC 18.

The cover layer 73 includes a cover film 101 and an adhesive 102. Thecover film 101 is made of, for example, an insulating material such aspolyimide. The adhesive 102 is made of, for example, an insulatingadhesive. The cover layer 73 thus has insulation property. In otherwords, the electrical resistance of each of the base layer 71 and thecover layer 73 is higher than the electrical resistance of theconductive layer 72.

The adhesive 102 is interposed between the cover film 101 and the uppersurface 71 a of the base layer 71 and the conductive layer 72. Theadhesive 102 adheres the cover film 101 to the upper surface 71 a of thebase layer 71 and the conductive layer 72.

The cover layer 73 has a substantially constant thickness and covers theupper surface 71 a of the base layer 71 and the conductive layer 72.Therefore, the cover layer 73 protrudes (rises) from the upper surface73 b at a position where the conductive layer 72 is provided. Asillustrated in FIG. 3 , the cover layer 73 has a plurality ofprotrusions 111, 112, and 113.

As illustrated in FIG. 4 , the protrusion 111 is a part of the coverlayer 73 that covers the ground wiring 91. The protrusion 111 protrudesfrom the upper surface 73 b along the ground wiring 91 and extends alongthe ground wiring 91. The protrusion 111 is thus located between the pad81 and the pad 83 and between the pad 81 and the pad 84 in a directionalong the upper surface 71 a of the base layer 71. The protrusion 111 islocated also between the underfill 69 and the pad 83 and between theunderfill 69 and the pad 84.

The protrusion 111 has two side surfaces 111 a and 111 b. The sidesurface 111 a is an example of a first protruding surface and aprotruding surface. The side surfaces 111 a and 111 b protrude (stickout, rise) from the upper surface 73 b along the ground wiring 91, andface in a direction intersecting the direction in which the uppersurface 73 b faces.

The side surface ilia is closer to the pad 83 than the side surface 111b, and is closer to the pad 84 than the side surface 111 b. The sidesurface 111 b is located on the opposite side of the side surface 111 a.The side surface 111 b is closer to the pad 81 than the side surface 111a.

As illustrated in FIG. 5 , the protrusion 112 is a part of the coverlayer 73 that covers the ground wiring 92. The protrusion 112 protrudesfrom the upper surface 73 b along the ground wiring 92 and extends alongthe ground wiring 92. The protrusion 112 is thus located between the GMAwiring 87 and the GMA wiring 88 in the direction along the upper surface71 a of the base layer 71.

The protrusion 112 has two side surfaces 112 a and 112 b. The sidesurfaces 112 a and 112 b protrude from the upper surface 73 b along theground wiring 92, and face in the direction intersecting the directionin which the upper surface 73 b faces. The side surface 112 a is closerto the GMA wiring 88 than the side surface 112 b. The side surface 112 bis located on the opposite side of the side surface 112 a. The sidesurface 112 b is closer to the GMA wiring 87 than the side surface 112a.

As illustrated in FIG. 6 , the protrusion 113 is a part of the coverlayer 73 that covers the ground wiring 93. The protrusion 113 protrudesfrom the upper surface 73 b along the ground wiring 93 and extends alongthe ground wiring 93. The protrusion 113 is thus located between the pad82 and the GMA wiring 87 in the direction along the upper surface 71 aof the base layer 71.

The protrusion 113 has two side surfaces 113 a and 113 b. The sidesurfaces 113 a and 113 b protrude from the upper surface 73 b along theground wiring 93, and face in the direction intersecting the directionin which the upper surface 73 b faces. The side surface 113 a is closerto the GMA wiring 87 than the side surface 113 b. The side surface 113 bis located on the opposite side of the side surface 113 a. The sidesurface 113 h is closer to the pad 82 than the side surface 113 a.

As illustrated in FIG. 3 , the cover layer 73 has a plurality ofexposure holes 121, 122, 123, and 124 and a plurality of through holes125, 126, and 127. The exposure holes 123 and 124 are an example of asecond hole. The through holes 125, 126, and 127 are an example of afirst hole.

The exposure holes 121, 122, 123, and 124 and the through holes 125,126, and 127 penetrate the cover layer 73 in the Z-direction. Theexposure holes 121, 122, 123, and 124 and the through holes 125, 126,and 127 are thus open to the upper surface 73 b and the lower surface 73a.

As illustrated in FIG. 4 , the exposure hole 121 exposes the pad 81. Inother words, the cover layer 73 does not cover the pad 81 in a partwhere the exposure hole 121 is provided. As illustrated in FIG. 6 , theexposure hole 122 exposes the pad 82. As illustrated in FIG. 4 , theexposure hole 123 exposes the pad 83. The exposure hole 124 exposes thepad 84.

The through holes 125, 126, and 127 are spaced from the conductive layer72 in the direction along the upper surface 71 a. The through holes 125,126, and 127 thus do not expose the conductive layer 72. In other words,the through holes 125, 126, and 127 do not overlap the conductive layer72 in the Z-direction.

As illustrated in FIG. 3 , the through hole 125 is located between thepad 81 and the pad 83, between the pad 81 and the pad 84, and betweenthe pad 81 and the power supply wiring 86. In addition, the through hole125 is located between the underfill 69 and the solder 95 and betweenthe underfill 69 and the solder 96 in the direction along the uppersurface 71 a of the base layer 71.

The through hole 125 is located between the ground wiring 91 and the pad83 and between the ground wiring 91 and the power supply wiring 86.Further, the through hole 125 is located between the side surface 111 aof the protrusion 111 and the exposure hole 123 in the direction alongthe upper surface 71 a of the base layer 71. Further, the through hole125 is located in the vicinity of an end 111 c of the side surface 111 ain a direction in which the side surface 111 a of the protrusion 111extends.

The through hole 126 is located between the GMA wiring 87 and the GMAwiring 88. The through hole 126 is located between the ground wiring 92and the GMA wiring 87. Further, the through hole 126 is located betweenthe side surface 112 a of the protrusion 112 and the GMA wiring 87 inthe direction along the upper surface 71 a of the base layer 71.

The through hole 127 is located between the pad 82 and the GMA wiring87. The through hole 127 is located between the ground wiring 93 and thepad 82. Further, the through hole 127 is also located between the sidesurface 113 a of the protrusion 113 and the pad 82 in the directionalong the upper surface 71 a of the base layer 71.

As illustrated in FIG. 6 , the through hole 127 exposes the uppersurface 71 a of the base layer 71 and the conductor 39. In other words,the cover layer 73 does not cover the conductor 89 in a part where thethrough hole 127 is provided. However, a part of the underfill 69 fillsthe through hole 127 and covers the conductor 89. That is, a part of theunderfill 69 is located in the through hole 127.

As illustrated in FIGS. 4 and 5 , through holes 131 and 132 are providedin the base layer 71. The through holes 131 and 132 are an example of athird hole. The through holes 131 and 132 penetrate the base layer 71 inthe −direction. The through holes 131 and 132 are thus open to the uppersurface 71 a and the lower surface 71 b.

The through hole 131 has substantially the same shape as the throughhole 125 of the cover layer 73. The through hole 131 overlaps thethrough hole 125 in the Z-direction and communicates with the throughhole 125. The shape of the through hole 131 may be different from theshape of the through hole 125.

The through hole 132 has substantially the same shape as the throughhole 126 of the cover layer 73. The through hole 132 overlaps thethrough hole 126 in the Z-direction and communicates with the throughhole 126. The shape of the through hole 132 may be different from theshape of the through hole 126.

Through holes 135 and 136 are provided in the ground layer 74 and thecover layer 75. Each of the through holes 135 and 136 penetrates theground layer 74 and the cover layer 75 in the Z-direction.

The through hole 135 has substantially the same shape as the throughhole 131 of the base layer 71. The through hole 135 overlaps the throughhole 131 in the Z-direction and communicates with the through hole 131.The shape of the through hole 135 may be different from the shape of thethrough hole 131.

The through hole 136 has substantially the same shape as the throughhole 132 of the base layer 71. The through hole 136 overlaps the throughhole 132 in the Z-direction and communicates with the through hole 132.The shape of the through hole 136 may be different from the shape of thethrough hole 132.

The reinforcing plate 68 is attached to the FTC 18 so as to cover thelower surface 71 b of the base layer 71. Thus, the base layer 71 islocated between the cover layer 73 and the reinforcing plate 68. Therigidity of the reinforcing plate 68 is higher than the rigidity of thebase layer 71 and higher than the rigidity of the cover layer 73. Thereinforcing plate 68 has through holes 141 and 142. The through holes141 and 142 are an example of a fourth hole. The through holes 141 and142 penetrate the reinforcing plate 68 in the Z-direction.

The through hole 141 has substantially the same shape as the throughhole 131 of the base layer 71. The through hole 141 overlaps the throughholes 131 and 135 in the Z-direction and communicates with the throughhole 131 through the through hole 135. The shape of the through hole 141may be different from the shape of the through hole 131.

The through hole 142 has substantially the same shape as the throughhole 132 of the base layer 71. The through hole 142 overlaps the throughholes 132 and 136 in the Z-direction and communicates with the throughhole 132 through the through hole 136. The shape of the through hole 142may be different from the shape of the through hole 132.

The through holes 125, 126, 131, 132, 135, 136, 141, and 142 arehollowed out and are not filled with a solid or a liquid. Therefore, theinside of the through holes 125, 126, 131, 132, 135, 136, 141, and 142is filled with gas in the casing 11 or is in a vacuum. Note that thethrough holes 125, 126, 131, 132, 135, 136, 141, and 142 are not limitedto the example. In addition, it is possible that the through holes 131,132, 135, 136, 141, and 142 are not provided. In such a case, thethrough holes 125 and 126 expose the upper surface 71 a of the baselayer 71.

Hereinafter, a method for mounting a component on the FPC 18 is partlyexemplified. The method for mounting a component on the FPC 18 is notlimited to the following method, and other methods may be used. First,solder paste (solder 95 and 96) is supplied to the pads 83 and 84 by,for example, printing or coating. Further, the solder paste may besupplied to the pads 81 and 82.

Next, the preamplifier 65 is mounted on the pads 81 and 82. Further, aterminal of the VCM 16 is mounted on the pad 83. Next, the FPC 18 isheated in a reflow furnace, so that the solder paste and the solder ballare melted. As a result, the terminals 65 a and 65 b of the preamplifier65 are bonded to the pads 81 and 82, the terminal of the VCM 16 isbonded to the Pad 83, and the solder 96 covers the pad 84. At this time,as illustrated in FIG. 4 , flux F mixed with or separately supplied tothe solder 95 and 96 may flow out of the solder 95 and 96.

Next, the underfill 69 is supplied between the preamplifier 65 and theFPC 13. The underfill 69 is also supplied to the through hole 127 tocover the conductor 89. At this time, in a case where the flux F ismixed with the underfill 69, a substance that may contaminate the HDD 10may be generated. For example, a crumbly sponge-like substance may begenerated. However, the HDD 10 according to this embodiment can reducethe mixing of the flux F and the underfill 69.

As illustrated in FIG. 4 , the flux F flows out of the solder 95supplied to the pad 83, for example, and wets and spreads along theupper surface 73 h of the cover layer 73. The flux F also flows out ofthe solder 96 supplied to the pad 84. When the flux F reaches thethrough hole 125, which is open to the upper surface 73 b, the flux Fstays at the edge of the through hole 125 due to surface tension. Thatis, the through hole 125 can block the flux F.

The flux F may flow into the through hole 125. In such a case, the fluxF accumulates in the through holes 125, 131, 135, and 141 or isdischarged through the through holes 125, 131, 135, and 141. Thus, thethrough hole 125 can block the flux F.

The flux F may go over the through hole 125 or bypass the through hole125 to wet and spread toward the underfill 69. However, the flux F isblocked by the side surface 111 a of the protrusion 111.

The flux F that has bypassed the through hole 125 may flow along theside surface 111 a of the protrusion 111. The flux F spreads from theend 111 c of the side surface 111 a when reaching the end 111 c.However, since the through hole 125 is provided in the vicinity of theend 111 c, the flux F flows into the through hole 125. As describedabove, the side surface 111 a of the protrusion 111 and the through hole125 between the solder 95 and 96 and the underfill 69 block the flux F.

The through hole 127 illustrated in FIG. 6 is formed so as to block theflux F and allow the underfill 69 to flow in. For example, the angle ofthe edge of the through hole 127 is partially different. Thus, of theedge of the through hole 127, a part thereof close to the underfill 69allows the underfill 69 to pass therethrough. On the other hand, of theedge of the through hole 127, a part thereof close to the solder blocksthe flux F. Note that the through hole 127 is not limited to theexample.

Next, the underfill 69 is cured by, for example, heat. This allows theunderfill 69 to fix the preamplifier 65 to the FPC 18. Next, the FPC 18is cleaned by, for example, ultrasonic cleaning, and the flux F isremoved. Thus, the mounting of the component on the FPC 18 is completed.

In the HDD 10 according to the first embodiment described above, the FPC18 includes the base layer 71, the conductive layer 72, and the coverlayer 73 having insulation property. The base layer 71 has the uppersurface 71 a having insulation property. The conductive layer 72overlays the upper surface 71 a and includes a first conductor (pads 81and 82, and GMA wiring 87) and a second conductor (pads 83 and 84, andGMA wiring 88) spaced from the first conductor. The cover layer 73covers at least a part of the upper surface 71 a and at least a part ofthe conductive layer 72. The FPO 18 is provided with the through holes125, 126, and 127. The through holes 125, 126, and 127 are locatedbetween the first conductors 81, 82, and 87 and the second conductors83, 84, and 88 with spacing from the conductive layer 72 and penetratethe cover layer 73. For example, the preamplifier 65 attached to the pad31 may be fixed to the FPC 18 with the underfill 69 while the pads 83and 84 may be applied with the solder 95 and 96. With the pad 81 and thepads 83 and 84 arranged at short intervals, the flux F may flow out ofthe solder 95 and 96 to the underfill 69. In such a case the underfill69 may mix with the flux F of the solder 95 and 96, causing a substancethat can contaminate the HDD 10. However, in the HDD 10 of thisembodiment, the through hole 125 extends between the pad 81 and the pads83 and 84. Thus, the through hole 125 can work to block the flux F,flowing out of the solder 95 and 96 attached to the pads 83 and 84,before reaching the underfill 69. As such, in spite of proximity betweenthe pad 81 and the pads 83 and 84, the HDD 10 according to thisembodiment can prevent the flux F and the underfill 69 from being mixed,lowering the possibility to contaminate the HDD 10. In other words, theHDD 10 can reduce the influence arising from the close arrangement ofthe pad 81 and the pads 83 and 84. In addition, in the HDD 10 accordingto this embodiment, the hollow, through holes 125, 126, and 127 caninsulate the first conductors 81, 82, and 87 from the second conductors83, 84, and 88. Thus, in spite of proximity between the first conductors81, 82, and 87 and the second conductors 83, 34, and 88, the HDD 10according to this embodiment can prevent occurrence of short circuit ornoise transmission between the first conductors 81, 82, and 87 and thesecond conductors 83, 84, and 88. In other words, the HDD 10 can reducethe influence arising from the close arrangement of the first conductors81, 82, and 87 and the second conductors 83, 84, and 88.

For example, the potential difference between the two sets of GMA wiring87 and 88 is larger than the potential difference between the signalwiring 85 and the power supply wiring 86. In general, dielectricbreakdown may occur in an insulator such as the cover layer 73 betweentwo interconnections having a large potential difference. In thisembodiment, however, the through hole 126 filled with gas or in a vacuumextends between the GMA wirings 87 and 88. The electrical resistance ofthe gas or the vacuum space is higher than the electrical resistance ofa solid such as polyimide. Because of this, the through hole 126 canprevent occurrence of dielectric breakdown between the two GMA wirings87 and 88 having a large potential difference. In addition, the gas orthe vacuum space has a lower thermal conductivity than a solid such aspolyimide. Thus, the through hole 126 can work to prevent heat transferbetween the two sets of GMA wiring 87 and 88.

For example, while traveling across the signal wiring 85 for ahigher-speed signal transmission, the signal is more susceptible tonoise from the power supply wiring 86 caused by parasitic impedance, forexample. However, in this embodiment, the through hole 125 filled withgas or in a vacuum extends between the signal wiring 85 and the powersupply wiring 86. Thus, the through hole 125 can work to prevent noisetransmission between the signal wiring 85 and the power supply wiring86.

The preamplifier 65 is connected to the pad 81. The underfill 69 extendsbetween the preamplifier 65 and the FPC 18. The solder 95 and 96 adhereto the pads 83 and 84. The through hole 125 is located between theunderfill 69 and the solder 95 and 96. Thereby, the through hole 125 canblock the flux F flowing out of the solder 95 and 96 before reaching theunderfill 69. Consequently, the HDD 10 according to this embodiment canprevent the flux F and the underfill 69 from being mixed.

The cover layer 73 has the lower surface 73 a and the upper surface 73b. The lower surface 73 a faces the upper surface 71 a. The uppersurface 73 b is opposite the lower surface 73 a. The cover layer 73 isprovided with the exposure holes 123 and 124. The exposure holes 123 and124 are open to the upper surface 73 b and expose the pads 83 and 84.The FPC 18 has the side surface 111 a between the pad 81 and the pads 83and 84 in the direction along the upper surface 71 a. The side surface111 a protrudes from the upper surface 73 b. The flux F may flow out ofthe solder 95 and 96 attached to the pads 83 and 34 and spread over theupper surface 73 b. The flux F is, however, blocked by the protrudingside surface 111 a on the upper surface 73 b before reaching theunderfill 69. Thus, the HDD 10 according to this embodiment can preventthe flux F and the underfill 69 from being mixed.

The through hole 125 is located between the side surface 111 a and theexposure holes 123 and 124 in the direction along the upper surface 71a. Thereby, the through hole 125 can block the flux F out of the solder95 and 96 attached to the pads 83 and 84, before the side surface 111 ablocks. As a result, in the HDD 10 according to this embodiment, it ispossible to prevent the flux F from flowing over the side surface 111 a,even if it has a relatively low height, to reach the underfill 69.

The conductive layer 72 includes the sets of ground wiring 91, 92, and93. The ground wiring sets 91, 92, and 93 are located between the firstconductors 81, 82, and 87 and the second conductors 83, 84, and 88, andare electrically connected to the ground. The side surface 111 aprotrudes from the upper surface 73 b along the ground wiring 91. Theside surface 111 a can be formed on the cover layer 73, for example, bystacking the cover layers 73 on the ground wiring 91. This eliminatesthe necessity to add special steps for forming the side surface 111 a,which can prevent cost increase in the HDD 10 of this embodiment.Further, the ground wiring sets 91, 92, and 93 can serve to preventoccurrence of short circuit due to dielectric breakdown or noisetransmission due to parasitic impedance between the first conductors 81,82, and 87 and the second conductors 83, 84, and 88.

The through hole 125 is located adjacent to the end 111 c of the sidesurface 111 a in the direction in which the side surface 111 a extends.Thereby, the through hole 125 can block the flux F, when blocked by theside surface 111 a, for example, from flowing further around the end 111c of the side surface 111 a. Thereby, the HDD 10 according to thisembodiment can prevent the flux F and the underfill 69 from being mixed.

The reinforcing plate 68 has rigidity higher than the base layer 71 andis attached to the FPC 18. The base layer 71 is provided with thethrough hole 131 extending between the cover layer 73 and thereinforcing plate 68 and penetrating the base layer 71 to communicatewith the through hole 125. The reinforcing plate 68 is provided with thethrough hole 141 penetrating the reinforcing plate 68 to communicatewith the through hole 131. In other words, the through holes 125, 131,and 141 form a continuous hole penetrating the base layer 71, the coverlayer 73, and the reinforcing plate 68. Since the continuous hole has avolume larger than the through hole 125, the continuous hole can store,i.e., block a larger amount of flux F than the through hole 125. Thus,the HDD 10 according to this embodiment can prevent the flux F and theunderfill 69 from being mixed. Further, for cleaning purpose, a cleaningliquid can flow through the continuous hole. As a result, the cleaningliquid can effectively remove the stored flux F from the continuoushole.

The conductive layer 72 includes the conductor 89 exposed from thethrough hole 127. The underfill 69 is partly located in the through hole127 to cover the conductor 89. In general, supply and reflow of thesolder are conducted before supply of the underfill 69. Because of this,before supply of the underfill 69, i.e., without inflow of the underfill69, the through hole 127 can block the flux F flowing out of the solder.Further, after the underfill 69 is supplied, the underfill 69 covers theconductor 89. The underfill 69 thus can prevent the conductor 89 frombeing short-circuited or corroded.

The first conductors 81, 82, and 87 include the GMA wiring 87 extendingalong the upper surface 71 a. The second conductors 83, 84, and 88include the GMA wiring 88 extending along the GMA wiring 87. The coverlayer 73 covers the GMA wirings 87 and 88. The through hole 126 extendsbetween the GMA wiring 87 and the GMA wiring 88. In the HDD 10 accordingto this embodiment, the hollow, through hole 126 can insulate the GMAwiring 87 from, the GMA wiring 88. Consequently, the HDD 10 according tothis embodiment can prevent occurrence of short circuit or noisetransmission between the GMA wiring 87 and the GMA wiring 88.

Second Embodiment

Hereinafter, the second embodiment is described with reference to FIG. 7. In the following description of the plurality of embodiments,constituent elements having functions similar to those of theconstituent elements already described are denoted by the same referencenumerals as those of the constituent elements already described, and thedescription thereof may be omitted. Further, the plurality ofconstituent elements denoted by the same reference numerals do notnecessarily have all the functions and properties in common, and mayhave different functions and properties according to the embodiments.

FIG. 7 is an exemplary cross-sectional view illustrating a part of thefirst connection part 61 according to the second embodiment. Asillustrated in FIG. 7 , the FPC 18 of the second embodiment includes aresist 200 instead of the ground wiring 91 and the protrusion 111.

The resist 200 has a protrusion 201. The protrusion 201 protrudes fromthe upper surface 73 b of the cover layer 73. The resist 200 may bepartially provided in the exposure hole 121 and partially provided onthe upper surface 73 b as illustrated in the example of FIG. 7 , or,alternatively, may be provided simply on the upper surface 73 b.

The protrusion 201 is located between the pad 81 and the pad 83 andbetween the pad 81 and the pad 84 in the direction along the uppersurface 71 a of the base layer 71. The protrusion 111 is located alsobetween the underfill 69 and the pad 83 and between the underfill 69 andthe pad 84.

The protrusion 201 has two side surfaces 201 a and 201 b. The sidesurface 201 a is an example of the first, protruding surface and theprotruding surface. The side surfaces 201 a and 201 b protrude (stickout, rise) from the upper surface 73 b, and face in the directionintersecting the direction in which the upper surface 73 b faces.

The side surface 201 a is closer to the pad 83 than the side surface 201b, and is closer to the pad 84 than the side surface 201 b. The sidesurface 201 b is located on the opposite side of the side surface 201 a.The side surface 201 b is closer to the pad 81 than the side surface 201a. In a case where the flux F flows out of the solder 95, the flux F isblocked by the side surface 201 a of the protrusion 201.

The through hole 125 is located between the side surface 201 a of theprotrusion 201 and the exposure hole 123 in the direction along theupper surface 71 a of the base layer 71. Further, the through hole 125is located in the vicinity of an end of the side surface 201 a in adirection in which the side surface 201 a of the protrusion 201 extends.

As described above, the protrusions 111 and 201 can be provided invarious modes. For example, as described in the first embodiment, theprotrusion 111 and the side surfaces 111 a and 111 b may be provided byraising a part of the cover layer 73 due to the presence of a part ofthe conductive layer 72 such as the ground wiring 91. Alternatively, asdescribed in the second embodiment, the protrusion 201 and the sidesurfaces 201 a and 201 b may be provided by placing another member suchas the resist 200 on the upper surface 73 b of the cover layer 73.

Third Embodiment

Hereinafter, the third embodiment is described with reference to FIG. 8. FIG. 8 is an exemplary cross-sectional view illustrating a part of thefirst connection part 61 according to the third embodiment. Asillustrated in FIG. 8 , the FPC 18 of the third embodiment includes abent part 301 instead of the ground wiring 91 and the protrusion 111.The bent part 301 is a bent part of the FPC 18.

In the third embodiment, the reinforcing plate 68 has a bent part 302.The bent part 302 is a part of the reinforcing plate 68 bent by pressworking, for example. Further, the reinforcing plate 68 has a lowersurface 68 a, an upper surface 68 b, a stepwise lower surface 68 c, astepwise upper surface 68 d, and a slope 68 e. The upper surface 68 b isan example of a fifth surface. The slope 68 e is an example of a secondprotruding surface.

The lower surface 68 a and the stepwise lower surface 68 c are surfacesof the reinforcing plate 68 facing the −Z-direction. The lower surface68 a and the stepwise lower surface 68 c are disposed substantiallyparallel to each other. The stepwise lower surface 68 c is spaced, by Z,from the lower surface 68 a in the Z-direction.

The upper surface 68 b and the stepwise upper surface 68 d are surfacesof the reinforcing plate 68 facing the Z-direction. The upper surface 68b and the stepwise upper surface 68 d face the lower surface 71 b of thebase layer 71. The upper surface 68 b is located on the opposite side ofthe lower surface 68 a. The stepwise upper surface 68 d is located onthe opposite side of the stepwise lower surface 68 c. The upper surface68 b and the stepwise upper surface 68 d are disposed substantiallyparallel to each other. The stepwise upper surface 68 d is spaced, by fZ, from the upper surface 68 b in the Z-direction.

The bent part 302 is provided between the lower surface 68 a and thestepwise lower surface 68 c and between the upper surface 68 b and thestepwise upper surface 68 d. Stated differently, the bent part 302 bendsthe reinforcing plate 68 in a step shape such that the lower surface 68a and the stepwise lower surface 68 c are distinguished and the uppersurface 68 b and the stepwise upper surface 68 d are distinguished. Notethat the reinforcing plate 68 is not limited to the example.

The slope 68 e is provided in the bent part 302 and is located betweenthe upper surface 68 b and the stepwise upper surface 68 d. The slope 68e extends diagonally with respect to the upper surface 68 b and thestepwise upper surface 68 d between the upper surface 68 b and thestepwise upper surface 68 d. The slope 68 e may extend so as to beorthogonal to the upper surface 68 b and the stepwise upper surface 68d.

The slope 68 e protrudes (sticks out, rises) from the upper surface 68 balong the bent part 302, and faces in a direction intersecting thedirection in which the upper surface 68 b faces. The bent part 302 andthe slope 68 e are located between the pad 81 and the pad 83 and betweenthe pad 81 and the pad 84 in the direction along the upper surface 71 aof the base layer 71.

The cover layer 73 further includes a stepwise upper surface 73 d and aslope 73 e. The slope 73 e is an example of the first protrudingsurface. The stepwise upper surface 73 d is disposed substantiallyparallel to the upper surface 73 b. The stepwise upper surface 73 d isspaced, by +Z direction, from the upper surface 73 b in the Z-direction.In the third embodiment, the exposure hole 121 is open to the stepwiseupper surface 73 d. On the other hand, the exposure hole 123 is open tothe upper surface 73 b.

The bent part 301 is provided between the upper surface 73 b and thestepwise upper surface 73 d. Stated differently, the bent part 301 bendsthe FPC 18 in a step shape such that the upper surface 73 b and thestepwise upper surface 73 d are distinguished. Note that the FPC 18 isnot limited to the example.

The slope 73 e is provided in the bent part 301 and is located betweenthe upper surface 73 b and the stepwise upper surface 73 d. The slope 73e extends diagonally with respect to the upper surface 73 b and thestepwise upper surface 73 d between the upper surface 73 b and thestepwise upper surface 73 d. The slope 73 e may extend so as to beorthogonal to the upper surface 73 b and the stepwise upper surface 73d.

The bent part 301 of the FPC 18 is formed by attaching the FPC 18 to thereinforcing plate 68 having the bent part 302. The bent part 301 of theFPC 18 is thus provided along the bent part 302 of the reinforcing plate68.

The slope 73 e protrudes (sticks out, rises) from the upper surface 73 balong the bent parts 301 and 302, and faces in a direction intersectingthe direction in which the upper surface 73 b faces. In other words, theslope 73 e protrudes from the upper surface 73 b along the slope 68 e ofthe reinforcing plate 68.

The bent part 301 and the slope 73 e are located between the pad 81 andthe pad 83 and between the pad 81 and the pad 84 in the direction alongthe upper surface 71 a of the base layer 71. Further, the bent part 301and the slope 73 e are located also between the underfill 69 and the pad83 and between the underfill 69 and the pad 84. In a case where the fluxF flows out of the solder 95, the flux F is blocked by the slope 73 e.

In the HDD 10 of the third embodiment described above, the reinforcingplate 68 has rigidity higher than the base layer 71 and is attached tothe FPC 18. The reinforcing plate 68 has the upper surface 68 b facingthe FPC 18 and the slope 68 e protruding from the upper surface 68 b.The slope 73 e protrudes from the upper surface 73 b along the slope 68e. The slope 73 e can be included in the cover layer 73, for example, byattaching the FPC 18 to the upper surface 68 b having the slope 68 e.This eliminates the need to add special steps for forming the slope 73e, leading to preventing cost increase in the HDD 10 of this embodiment.

In the embodiments described above, the preamplifier 65 is an example ofthe component; however, the relay connector 66, the sensor 67, oranother component may be an example of the component. The protrusions111, 112, and 113 and the through holes 125, 126, and 127 are providedin the first connection part 61; however, they may be provided inanother part such as the second connection part 62.

In the above description, the prevention/reduction is defined as, forexample, preventing the occurrence of an event, an action, or aninfluence, or reducing the degree of the event, the action, or theinfluence. Further, in the above description, the limit/restriction isdefined as, for example, preventing movement or rotation, or allowingmovement or rotation within a predetermined range and preventingmovement or rotation beyond the predetermined range.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. A disk device comprising: a magnetic disk; amagnetic head configured to read and write information from and to themagnetic disk; a flexible printed circuit board electrically connectedto the magnetic head, the flexible printed circuit board including: afirst layer including a first surface having insulation property, asecond layer overlaying the first surface and having conductiveproperty, the second layer including a first conductor and a secondconductor spaced from the first conductor, and a third layer havinginsulation property and covering at least a part of the first surfaceand at least a part of the second layer, the flexible printed circuitboard provided with a first hole that is located between the firstconductor and the second conductor with spacing from the second layerand penetrates the third layer; a component connected to the firstconductor; an underfill extending between the component and the flexibleprinted circuit board; and solder attached to the second conductor,wherein the first hole is located between the underfill and the solder,the third layer with a second hole exposing the second conductorincludes a second surface facing the first surface, and a third surfaceopposite the second surface and to which the second hole is open, andthe flexible printed circuit board includes a first protruding surfacebetween the first conductor and the second conductor in a directionalong the first surface, the first protruding surface protruding fromthe third surface.
 2. The disk device according to claim 1, wherein thefirst hole is located between the first protruding surface and thesecond hole in the direction along the first surface.
 3. The disk deviceaccording to claim 1, wherein the second layer includes ground wiringthat is located between the first conductor and the second conductor andis electrically connected to a ground, and the first protruding surfaceprotrudes from the third surface along the ground wiring.
 4. The diskdevice according to claim 1, wherein the first hole is located adjacentto an end of the first protruding surface in a direction in which thefirst protruding surface extends.
 5. The disk device according to claim1, further comprising: a wall having rigidity higher than the firstlayer and attached to the flexible printed circuit board, wherein thewall has a fifth surface facing the flexible printed circuit board and asecond protruding surface protruding from the fifth surface, and thefirst protruding surface protrudes from the third surface along thesecond protruding surface.
 6. The disk device according to claim 1,wherein the first conductor includes first wiring extending along thefirst surface, the second conductor includes second wiring extendingalong the first wiring, and the third layer covers the first wiring andthe second wiring.
 7. A disk device comprising: a magnetic disk; amagnetic head configured to read and write information from and to themagnetic disk; a flexible printed circuit board electrically connectedto the magnetic head, the flexible printed circuit board including: afirst layer including a first surface having insulation property, asecond layer overlaying the first surface and having conductiveproperty, the second layer including a first conductor and a secondconductor spaced from the first conductor, and a third layer havinginsulation property and covering at least a part of the first surfaceand at least a part of the second layer, the flexible printed circuitboard provided with a first hole that is located between the firstconductor and the second conductor with spacing from the second layerand penetrates the third layer; a wall having rigidity higher than thefirst layer and attached to the flexible printed circuit board, whereinthe first layer is provided with a third hole located between the thirdlayer and the wall, the third hole penetrating the first layer tocommunicate with the first hole, and the wall is provided with a fourthhole penetrating the wall to communicate with the third hole.